There are a multiplicity of such aids already known, which vary greatly in complexity and effectiveness. For example, one known aid comprises a thick plastic overseat having adjustable brackets on its underside to engage and locate the overseat on an ordinary seat of a water closet. This aid is passive and merely enables a user to sit down at a higher than standard height, so that less effort is required to stand up again. It has also been proposed to mount a toilet set on a hydraulically or electrically powered mechanism which can raise and lower the seat (and a person thereon) between a low seating position for using the toilet and a raised position in which the person can straighten his or her legs and move his or her body forwards to achieve a standing position. However, all the aids known at the present time appear to give rise to problems for such persons, including problems of initialing the aid, lack of sufficient assistance afforded by most of the aids, and with those aids which offer lifting assistance, problems of cost, mechanical complexity and physical bulk.